Mechanism of Pancreatic Carcinogenesis

胰腺癌发生机制

基本信息

批准号：
8987762
负责人：
Martin Ernesto Fernandez-Zapico
金额：
$ 34.41万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-01-01 至 2020-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8987762
关键词：
Adenocarcinoma Cell Affect Animal Model Automobile Driving Binding Biological Biological Assay Cancer Etiology Cause of Death Cell Survival Cell physiology Cells Cessation of life ChIP-seq Chimeric Proteins Chromatin Clinical Complex Crystallins Data Development Diagnosis Disease Epithelial Epithelial Cells Excision Foundations GLI Family Protein GLI gene Gene Activation Gene Expression Gene Targeting Genes Genetic Genetic Transcription Growth Factor Histones Homeobox Genes Human Immunoprecipitation In Vitro Investigation KRAS2 gene Knowledge Lead Lesion Lysine Malignant Neoplasms Malignant neoplasm of pancreas Maps Mediating Menin Methyltransferase Modeling Molecular Mus Mutate Mutation Neoplasms Nucleosomes Oncogenic Operative Surgical Procedures Pain Pancreas Pancreatic Ductal Adenocarcinoma Pathogenesis Pathway interactions Patients Play Proteins Recruitment Activity Regulation Reporting Role Sampling Staging Structure Testing Therapeutic Intervention Transcriptional Activation Transcriptional Regulation Work base carcinogenesis cofactor effective therapy genetic approach histone methyltransferase histone modification in vivo inhibitor/antagonist insight lens lens protein leukemia mortality mouse model mutant new therapeutic target novel novel therapeutic intervention overexpression pancreatic neoplasm promoter protein complex protein protein interaction public health relevance research study small molecule therapeutic target transcription factor transcriptome sequencing tumor tumor initiation

项目摘要

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease for which there is currently no effective treatment. Therefore, there is an urgent need to understand the molecular mechanisms underlying the pathobiology of PDAC so that new therapeutic approaches can be developed to target this dismal disease. The transcription factor, GLI1, is increased in PDAC and plays important roles in pancreatic carcinogenesis by activating transcription of key genes involved in PDAC initiation. Multiple lineage leukemia 1 (MLL1) histone methyltransferase (HMT) is a protein well known for its role in leukemia, where translocations of the MLL1 gene lead to formation of oncogenic fusion proteins. MLL1 is reported to be associated with many actively transcribed genes and to regulate the expression of certain loci, e.g., HOX genes. MLL1 is not mutated in PDAC and has not been previously implicated in the pathogenesis of this disease. However, we have found that MLL1 is overexpressed in human PDAC samples. Significantly, we have made the novel discovery that the MLL1 protein complex and an associated protein, lens epithelial derived growth factor (LEDGF) interact with GLI1 in PDAC cells to regulate the activation of GLI1 target genes, e.g., TGFß1 and IL6Ra. We hypothesize that the MLL1 complex and GLI1 interact in pancreatic epithelial cells to coordinately activate transcription of key genes driving the development and progression of preneoplastic lesions leading to PDAC. Based on our findings, we propose to elucidate the mechanisms by which GLI1 and MLL1 interact to regulate transcription and establish the biological significance of this HMT complex in GLI1-induced PDAC. We propose three Aims: First, we will examine the physical interactions between GLI1 and MLL1 complex proteins to determine which MLL1 complex protein(s) interacts directly with GLI1. We will also perform binding assays to map which regions of GLI1 are important for GLI1/MLL1 interactions. Second, we will investigate the mechanisms by which GLI1 and the MLL1 complex interact at gene promoters to regulate transcription. We will determine the promoter recruitment mechanism targeting the MLL1 complex to GLI1 target genes. We will also determine the specific alterations in histone modifications or nucleosome organization associated with binding of GLI1-MLL1 complex to the target genes. In addition, we will use global approaches, RNA-seq and ChIP-seq, to identify additional target genes that are coordinately regulated by GLI1 and the MLL1 complex in PDAC cells. These data will be used to mechanistically ascertain if GLI1 is generally involved in recruiting the MLL1 complex in PDAC cells and if the co-occurrence of MLL1 and GLI1 at promoters is globally associated with changes in histone modifications, e.g., histone 3, lysine 4 trimethylation, associated with gene activation. Finally, we will utilize a wel-established genetic mouse model of PDAC to examine how genetic and small molecule inhibitor-mediated loss of MLL1 function affects the GLI1-dependent initiation of PDAC. These animal model experiments will provide a test for our hypothesis in vivo and will evaluate the feasibility of targeting the MLL1 complex to inhibit GLI1-driven carcinogenesis in PDAC.

描述（申请人提供）：胰腺导管腺癌（PDAC）是一种致命的疾病，目前尚无有效的治疗方法，因此，迫切需要了解 PDAC 病理学的分子机制，以便开发新的治疗方法。转录因子 GLI1 在 PDAC 中增加，并通过激活参与 PDAC 多谱系启动的关键基因的转录在胰腺癌发生中发挥重要作用。白血病 1 (MLL1) 组蛋白甲基转移酶 (HMT) 是一种因其在白血病中的作用而闻名的蛋白质，MLL1 基因的易位导致致癌融合蛋白的形成，据报道 MLL1 与许多活跃转录的基因相关并调节白血病。某些基因座的表达，例如，HOX 基因在 PDAC 中未发生突变，并且之前并未涉及该疾病的发病机制。值得注意的是，我们发现 MLL1 蛋白复合物和相关蛋白晶状体上皮衍生生长因子 (LEDGF) 与 PDAC 细胞中的 GLI1 相互作用，调节 GLI1 靶标的激活。我们发现 MLL1 复合物和 GLI1 在胰腺上皮细胞中相互作用，协调激活驱动关键基因的转录。基于我们的发现，我们建议阐明 GLI1 和 MLL1 相互作用调节转录的机制，并确定该 HMT 复合物在 GLI1 诱导的 PDAC 中的生物学意义。首先，我们将检查 GLI1 和 MLL1 复合蛋白之间的物理相互作用，以确定哪些 MLL1 复合蛋白直接与 GLI1 相互作用。我们还将进行结合测定来绘制 GLI1 的哪些区域。 GLI1 对于 GLI1/MLL1 相互作用很重要。其次，我们将研究 GLI1 和 MLL1 复合物在基因启动子处相互作用以调节转录的机制。我们还将确定针对 GLI1 靶基因的启动子招募机制。确定与 GLI1-MLL1 复合物与靶基因结合相关的组蛋白修饰或核小体组织的具体改变。此外，我们将使用全局方法、RNA-seq 和 ChIP-seq，以确定 PDAC 细胞中 GLI1 和 MLL1 复合物协调调节的其他靶基因。这些数据将用于机械地确定 GLI1 是否通常参与 PDAC 细胞中 MLL1 复合物的募集以及 MLL1 和 GLI1 是否共存。 at 启动子与组蛋白修饰的变化全局相关，例如，与基因激活相关的组蛋白 3、赖氨酸 4 三甲基化。我们建立了完善的 PDAC 遗传小鼠模型，以研究遗传和小分子抑制剂介导的 MLL1 功能丧失如何影响 GLI1 依赖性 PDAC 启动。这些动物模型实验将为我们的假设提供体内测试，并评估其可行性。靶向 MLL1 复合物抑制 PDAC 中 GLI1 驱动的致癌作用。